One of the more important changes to the backend is that the code has been changed to allow for multithreaded usage of the library (i.e., clients such as PulseView can now call libsigrokdecode API functions from different threads without any issues).

All protocol decoders shipped with libsigrokdecode have now been converted to the new PDv3 API that was introduced in libsigrokdecode 0.5.0. This usually means simpler and easier to understand protocol decoders as well as (quite massive, in some cases) performance improvements.

As mentioned in the 0.5.0 release notes, support for the old PD API has now been dropped, as all PDs have been converted to the PDv3 API. If you have any out-of-tree protocol decoders, please consider contributing them to mainline libsigrokdecode to benefit from such updates automatically. If that's not possible or desirable for some reasons, you can usually update your local PDs to the PDv3 API relatively easily (check the wiki page, or any of the 85 already converted PDs, for details).

See the NEWS file for a much more detailed list of changes, or browse the git history for even more details.